A number of anchoring systems are known with which a vessel can lie anchored while loading for example crude oil from an oilfield connected by one or more pipelines.
For use in deep water it is in particular beneficial to use an anchoring system with a subsea buoy anchored to the seabed. A common feature for all anchoring systems of said type is that the forces acting on the anchor lines and the loading/unloading pipelines are reduced due to the use of a subsea buoy, because the impact of weather and wind decreases as the water depths increase. Further, the vessels will if the subsea buoy is located deeper than the draught of the vessels, not collide with the subsea buoy. The connection to the vessel from the subsea buoy, for the anchoring and/or loading/unloading pipeline, is either via a surface buoy or directly between the vessel and the subsea buoy. Anchoring systems for which the loading pipeline and the anchoring per se are separated all the way from the seabed to the vessel are also known (ref: APL's SAL). Someg examples on anchoring systems of the above mentioned types are found in the patent publications U.S. Pat. No. 5,816,183, FR 2344442, DE 2752266 and NO 1999 1985.
Despite the above mentioned prior art a demand still exists for an anchoring system with which the subsea buoy can be lifted to the surface with all anchoring lines and loading lines connected, with all types of media in the loading lines, by relatively simple means. A demand also exists for an anchoring system that allows for a vessel to connect or disconnect in a similar way independent of which load that is to be loaded or unloaded, which means that the anchoring system can handle variations in buoyancy caused by variations or changes in the loading medium. Said variations in buoyancy can amount to several hundred metrical tons. A demand also exists for an anchoring system with a surface buoy constructed so that if the surface buoy is damaged or fails the subsea buoy and the below suspended elements will be deployed only a relatively short distance down into the sea, typically less than 20 meters.